Sökning: "RARE-EARTH ELEMENT"

Visar resultat 6 - 10 av 27 avhandlingar innehållade orden RARE-EARTH ELEMENT.

  1. 6. Microbially mediated formation of birnessite-type manganese oxides and subsequent incorporation of rare earth elements, Ytterby mine, Sweden

    Författare :Susanne Sjöberg; Christophe Dupraz; Rienk Smittenberg; Volker Brüchert; Helena Filipsson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; microbial diversity; manganese oxides; birnessite; rare earth elements; subterranean; Ytterby mine; geokemi; Geochemistry;

    Sammanfattning : Microbes exert extensive control on redox element cycles. They participate directly orindirectly in the concentration and fractionation of elements by influencing the partitioningbetween soluble and insoluble species. LÄS MER

  2. 7. Microbially mediated manganese oxides enriched in yttrium and rare earth elements in the Ytterby mine, Sweden

    Författare :Susanne Sjöberg; Christophe Dupraz; Per Persson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; manganese oxidizers; birnessite; yttrium and rare earth elements YREE ; biofilms; shallow subsurface; Ytterby mine; geomicrobiology; microbial geochemistry; manganoxiderare; birnessit; yttrium och sällsynta jordartsmetaller YREE ; underjordisk; Ytterby mine; geomikrobiologi; mikrobiell kemi; geokemi; Geochemistry;

    Sammanfattning : Microorganisms are able to manipulate redox reactions and thus exert extensive control on chemical speciation and element partitioning in nature, affecting the formation and dissolution of certain minerals. One of these redox active elements is manganese (Mn), which in its oxidized states (III/IV), commonly forms Mn oxide-hydroxide minerals. LÄS MER

  3. 8. The rule of hydrogen and rare earth metals in the formation of protective metal-oxides

    Författare :Bent N. Tveten; KTH; []
    Nyckelord :chromium; high-temperature corrosion; oxide growth; scale adherence; hydrogen; yttria; REM; reactive element effect; gas phase analysis;

    Sammanfattning : The effects of hydrogen and rare earth metal (REM) additionson the oxidation behavior of metals and alloys that formchromia, alumina and zirconia in 20 mbar O2and/or H2O have been investigated at elevated temperatures.The metal-gas reactions were studied by the use of isotopicallylabeled gas in combination with mass spectrometry and bymeasuring changes in the total pressure in a closed reactionchamber. LÄS MER

  4. 9. Multiplet computation methods for core level X-ray spectroscopy of transition metal and rare earth elements

    Författare :Xiao Cheng; Yi Luo; Marcus Lundberg; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; multiplet calculation; core level X-ray spectroscopy; transition metal; rare earth element; XAS; XPS; RIXS; Biotechnology; Bioteknologi;

    Sammanfattning : With the development of new generation synchrotron facilities, the performances of various X-ray spectroscopies have become more advanced. In order to interpret the X-ray spectrum experiments of various novel materials related to transition metal and rare earth elements, new advanced theoretical methods are required. LÄS MER

  5. 10. Experimental and Computational Magnetic Resonance Studies of Selected Rare Earth and Bismuth Complexes

    Författare :Vasantha Gowda; Oleg Antzutkin; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Chemistry of Interfaces; Gränsytors kemi;

    Sammanfattning : The rare-earth elements (REEs) and bismuth, being classified as the ‘most critical raw materials’ (European Raw Materials Initiatives, 2017), have a high economic importance to the EU combined with a high relative supply risk. REEs are highly important for the evolving technologies such as clean-energy applications, high-technology components, rechargeable batteries, permanent magnets, electric and hybrid vehicles, and phosphors monitors. LÄS MER